Zinc Sulphide: Zinc Sulphate, Ammonia and Carbon Disulphide in a Closed Digester (1900)

White zinc sulphide, fine enough for a pigment, made by heating zinc sulphate, ammonia and carbon disulphide together in a closed, stirred vessel. The run is over when the pressure has risen and fallen again. Source: Thorpe, Dictionary of Applied Chemistry vol. 5 (1913), Zinc, citing Eng. Pat. 11108 (1900). Unknown: ammonia of sp. gr. 0.91 has no head of its own yet. Carbon disulphide is poisonous and its vapour ignites easily. Picture drawn by Youblob.